Recent developments in modern turf construction have focussed on providing soil having freely draining sand and gravel profiles that allow grass grown thereon to serve as an all weather surface.
In order to achieve the desired level of permeability of such surfaces, the sand and gravel components of the soil must be precisely specified, and great care must be taken in the course of constructing the surface. As the sand and gravel components are derived from naturally occurring deposits, it is almost impossible to find deposits of these components that satisfy the required specification, and so costly and time consuming grading and washing processes are necessary to conform the naturally occurring deposits appropriately.
A further difficulty has arisen in sourcing of the naturally occurring deposits due to the high demand for sand and gravel over the last few hundred years in the building and civil engineering industries. This demand has normally been satisfied by sourcing naturally occurring deposits near to the major cities where the most demand arises. These deposits are becoming increasingly exhausted and the costs and delays associated with the transportation of these deposits from ever more distant pits and quarries are placing a burden on satisfying the demand cost effectively.
More recently, turf farming has developed as a sustainable form of intensive horticulture. Although turf farming may provide a more cost effective means of supplying turf, some variability in the nutrient and water supply to farmed turf can result because of local variations in the naturally sourced soil or other growth medium used. Also, the growth medium may serve as a source or carrier for disease causing organisms, and it is not unusual for farmed turf to experience an outbreak of disease.
In order to avoid the difficulties imposed by the requirements to grade and wash naturally occurring sand and gravel deposits and to transport them over long distances, and to better control nutrient and water supply and disease outbreaks in farmed turf, attention is now being focussed, particularly in the sports turf industry, on providing alternative, artificial turf growth surfaces which are derived from recycled products or replaceable resources but which have at least comparable or improved performance to soil having freely draining sand and gravel profiles.
Artificial surfaces for the growing of turf are still in their infancy, but some advances have been made in providing artificial surfaces that have excellent drainage capacity and good structural integrity to resist adverse weather conditions and physical damage, which features are ideally suited to support turf growth. Such features, for example, are provided by the artificial surface disclosed in Australian Patent No. 712,740 by the present inventor, the teachings of which are herein incorporated by reference. That artificial surface essentially comprises a cold mixture of rubber and a polymer modified bitumen emulsion, mixed in a proportion and laid under a controlled downward pressure sufficient to produce a water permeable and flexible surface facilitated by air pockets in the laid surface. Although not originally intended as a custom made surface to support turf growth, it has been found that the artificial surface of Australian Patent No. 712,740 will, to a minimal degree, support the growth of turf, albeit of indifferent quality. To achieve controllable and optimal turf growth on that surface requires further development and testing, a task that has been undertaken by the present inventor in arriving at the present invention.
It is an object of the present invention to overcome, or at least substantially ameliorate, the disadvantages and shortcomings of the prior art.
It is another object of the present invention to provide an artificial surface for the growing of turf forming grasses and other plants that allows root penetration and water drainage therethrough, as well as having good heat conductance for prolonging plant growth.
It is yet another object of the present invention to incorporate in the aforementioned artificial surface a plant nutrient source that allows slow release of the plant nutrient for growth of the turf forming grasses and other plants.